Vehicle air-conditioning system

ABSTRACT

A vehicle air-conditioning system includes a duct housing therein an evaporator, an air-mixing mechanism, and a heater core that are successively arranged along the direction in which air is delivered by a blower to flow through the duct. A temperature sensor for detecting the temperature of the evaporator is disposed upstream of the evaporator with respect to the direction in which the air flows through the duct. The temperature sensor has at least a portion inserted in the evaporator.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle air-conditioning system having a duct for discharging regulated air into the passenger's compartment of a vehicle, the duct housing therein a heat exchanger for performing heat exchange between air and a temperature-regulating medium which flow in the duct.

2. Description of the Related Art

Usually, vehicle air-conditioning systems include a temperature sensor for measuring the temperature of air immediately after the air has passed through a heat exchanger such as an evaporator or the like for the purpose of preventing the heat exchanger from being frozen.

For example, as shown in FIG. 8 of the accompanying drawings, a vehicle air-conditioning system disclosed in Japanese Laid-Open Patent Publication No. 2003-300410 has a casing 2 defining therein a passage 1 for discharging regulated air into the passenger's compartment of the vehicle. The vehicle air-conditioning system also includes an evaporator 3 disposed as a cooling heat exchanger in the casing 2. The evaporator 3 cools air flowing through the passage 1 by heat exchange between the air and a coolant that flows in the evaporator 3.

The passage 1 is divided by a partition plate 4 into a first passage 5 a and a second passage 5 b downstream of the evaporator 3. The casing 2 also houses a heater core 6 disposed as a heating heat exchanger downstream of the evaporator 3. Air-mixing doors, not shown, are disposed respectively in the first passage 5 a and the second passage 5 b between the evaporator 3 and the heater core 6 for adjusting the ratio between the flow rates of hot air heated by the heater core 6 and cool air bypassing the heater core 6.

A temperature sensor 7 for detecting the temperature of air immediately after it has passed through the evaporator 3 is disposed downstream of the evaporator 3. The temperature sensor 7 comprises a temperature detector 7 a and a cable 7 b, and is secured to a partition plate 8 which is part of the casing 2.

The casing 2 has a considerably long dimension in the directions indicated by the arrow A because the temperature sensor 7, the air-mixing doors (not shown), the partition plate 4, and the heater core 6 are disposed downstream of the evaporator 3.

The dimension in the directions indicated by the arrow A may be reduced by changing the position where the temperature sensor 7 is mounted or the layout of the air-mixing doors. However, the position or layout change would lower the accuracy of the temperature of the air measured by the temperature sensor 7 or prevent the air-mixing doors from controlling air flow rate and temperature effectively, resulting in a reduction in the air-conditioning capability of the vehicle air-conditioning system.

SUMMARY OF THE INVENTION

It is a major object of the present invention to provide a vehicle air-conditioning system which is capable of accurately detecting the temperature of a heat exchanger and of performing temperature adjustment with high accuracy, and is reduced in size.

According to the present invention, a vehicle air-conditioning system includes a duct for discharging regulated air into the passenger's compartment of a vehicle, and a heat exchanger disposed in the duct for allowing heat to be transferred between air flowing through the duct and a temperature-regulating medium flowing through the heat exchanger. A temperature sensor for measuring the temperature of the heat exchanger is disposed upstream of the heat exchanger with respect to the direction in which the air flows through the duct.

Generally, the duct has a relatively large space therein upstream of the heat exchanger with respect to the direction in which the air flows, for supplying the uniform air to the heat exchanger. Since the temperature sensor is disposed upstream of the heat exchanger with respect to the direction in which the air flows through the duct, the temperature sensor can be mounted in a desired position with increased freedom. The temperature sensor can thus be laid out in a position with respect to the heat exchanger for maximum heat exchange performance, and can measure the temperature of the heat exchanger accurately and reliably.

As the temperature sensor is not positioned downstream of the heat exchanger, other devices, e.g., an air-mixing mechanism, can be laid out as closely to the heat exchanger as possible downstream thereof. Therefore, the vehicle air-conditioning system can be greatly reduced in overall size, and the air-mixing mechanism can reliably perform air flow rate adjustment and temperature adjustment for highly accurate air-conditioning operation.

The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of the main portion of a vehicle air-conditioning system according to an embodiment of the present invention;

FIG. 2 is a fragmentary perspective view of an evaporator and a temperature sensor of the vehicle air-conditioning system shown in FIG. 1;

FIG. 3 is a plan view, partly in cross section, of the temperature sensor;

FIG. 4 is a schematic cross-sectional view showing another layout of the temperature sensor;

FIG. 5 is a schematic cross-sectional view showing still another layout of the temperature sensor;

FIG. 6 is a schematic cross-sectional view showing another layout of an air-mixing mechanism of the vehicle air-conditioning system shown in FIG. 1;

FIG. 7 is a schematic cross-sectional view showing still another layout of the air-mixing mechanism; and

FIG. 8 is a schematic cross-sectional view of a vehicle air-conditioning system disclosed in Japanese Laid-Open Patent Publication No. 2003-300410.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, a vehicle air-conditioning system 10 according to an embodiment of the present invention has a duct 14 defining a passage 12 therein for discharging temperature- and humidity-regulated air into the passenger's compartment of a vehicle. The vehicle air-conditioning system 10 includes a blower 16 disposed in the duct 14 at a position upstream with respect to the direction in which air flows in the passage 12, i.e., in the direction indicated by the arrow X, and an evaporator (cooling heat exchanger) 18 disposed in the duct 14 downstream of the blower 16. A heater core (heating heat exchanger) 20 is in the duct 14 downstream of the evaporator 18. An air-mixing mechanism 22 for mixing cool air and hot air with each other is mounted in the duct 14 on an inlet side of the heater core 20.

As shown in FIG. 2, the evaporator 18 includes fins 24 in which a coolant (temperature-regulating medium) flows. The evaporator 18 evaporates the coolant by allowing heat to be transferred between the coolant flowing in the fins 24 and air that is delivered by the blower 16 to flow in the passage 12 in the duct 14 along the direction indicated by the arrow X, and also cools the air flowing in the passage 12. A temperature sensor 26 for measuring the temperature of the evaporator 18 is disposed in the passage 12 upstream of the evaporator 18 with respect to the direction in which the air flows, i.e., the direction indicated by the arrow X.

The temperature sensor 26 comprises a thermistor, for example, and is held by a resin holder 28. The temperature sensor 26 has at least a portion inserted between adjacent ones of the fins 24 on an upstream side of the evaporator 18 with respect to the direction in which the air flows. The holder 28 has an integral tapered inserter 30 that has at least a portion also inserted into the fin 24 on the upstream side of the evaporator 18 with respect to the direction in which the air flows.

As shown in FIG. 3, the temperature sensor 26 includes an aluminum case 32 in the form of a bottomed hollow cylinder housing therein a thermistor chip 36 that is fixedly positioned in a closed tip end portion of the aluminum case 32 with a filler 34 disposed around the thermistor chip 36. Leads 38 extending from the thermistor chip 36 are connected to a harness 40 that extends out of the holder 28 through an end thereof. As shown in FIG. 2, a coupler 42 is connected to the end of the harness 40 remote from the holder 28. The coupler 42 is connected to a controller coupler, not shown.

As shown in FIG. 1, the air-mixing mechanism 22 includes an air-mixing damper 44 that is angularly movable arbitrarily in an angular range from an opening 0% to an opening 100% about an end thereof by a motor 46.

The heater core 20 is essentially identical in construction to the evaporator 18. The heater core 20 has hot water (heating medium) flowing circulatively therein, and heats the air flowing in the passage 12 in the duct 14 by allowing heat to be transferred between the hot water and the air flowing in the passage 12.

The duct 14 has branched downstream ends connected respectively to a defroster outlet, not shown, for ejecting air toward the inner surface of the front windshield of the vehicle, a face outlet, not shown, for ejecting air toward the head of a passenger, and a foot outlet, not shown, for ejecting air toward the feet of the passenger. Dampers, not shown, are angularly movably disposed in the defroster outlet, the face outlet, and the foot outlet, respectively.

Operation of the vehicle air-conditioning system 10 will be described below.

As shown in FIG. 1, when air is introduced into the duct 14 by the blower 16, the air moves along the passage 12 into the evaporator 18, which cools the air by heat exchange between the air and the coolant flowing in the evaporator 18. The cooled air is then supplied from the evaporator 18 to the air-mixing damper 44 of the air-mixing mechanism 22. The cooled air is divided into an air flow supplied to the heater core 20 and an air flow bypassing the heater core 20. The ratio between the flow rate of the cooled air supplied to the heater core 20 and the flow rate of the cooled air bypassing the heater core 20 is adjusted depending on the opening of the air-mixing damper 44.

In a region of the passage 12 downstream of the heater core 20, the hot air discharged from the heater core 20 and the cooled air bypassing the heater core 20 are mixed with each other into mixed air (temperature-regulated air). The mixed air (temperature-regulated air) is delivered to the defroster outlet, the face outlet, and the foot outlet.

According to the present embodiment, the temperature sensor 26 is disposed upstream of the evaporator 18 with respect to the direction in which the air flows through the passage 12. The duct 14 has a relatively large space in the passage 12 upstream of the evaporator 18 with respect to the direction in which the air flows, for supplying the uniform air to the evaporator 18. The temperature sensor 26 can thus be laid out in a position with respect to the evaporator 18 for maximum cooling performance, and can measure the temperature of the evaporator 18 accurately.

For example, as shown in FIG. 1, the temperature sensor 26 is disposed substantially centrally on the inlet side of the evaporator 18. Alternatively, as shown in FIG. 4, the temperature sensor 26 may be disposed at an upper end, in the direction indicated by the arrow B, of the evaporator 18, or as shown in FIG. 5, the temperature sensor 26 may be disposed at a lower end, in the direction indicated by the arrow C, of the evaporator 18.

The temperature sensor 26 is not positioned downstream of the evaporator 18 with respect to the direction in which the air flows through the passage 12. Consequently, other devices, e.g., the air-mixing mechanism 22, can be laid out as closely to the evaporator 18 as possible downstream thereof. Therefore, the vehicle air-conditioning system 10 can be greatly reduced in dimension along the direction indicated by the arrow X, and hence can easily be reduced in overall size.

The air-mixing mechanism 22 can be disposed closely to the evaporator 18 downstream thereof with respect to the direction in which the air flows, and can be positioned in any of various layouts. For example, the air-mixing mechanism 22 may be positioned in a layout shown in FIG. 6 or in a layout shown in FIG. 7. Therefore, the air-mixing mechanism 22 can be designed with increased freedom, and can reliably perform air flow rate adjustment and temperature adjustment for highly accurate air-conditioning operation.

The temperature sensor 26 as it is held by the holder 28 has at least a portion directly inserted between adjacent ones of the fins 24 on the upstream side of the evaporator 18 with respect to the direction in which the air flows. Therefore, the temperature sensor 26 can measure the temperature of the evaporator 18 easily and highly accurately for thereby reliably preventing the evaporator 18 from being frozen and controlling temperature adjustment highly accurately.

The holder 28 includes the tapered inserter 30 that includes at least a portion also directly inserted into the fin 24. Consequently, the holder 28 is firmly and reliably supported by the evaporator 18.

As the temperature sensor 26 is inserted into the fin 24 on the upstream side of the evaporator 18 with respect to the direction in which the air flows, the harness 40 is free from dew condensation which would otherwise occur if the temperature sensor 26 were inserted into the fin 24 on the downstream side of the evaporator 18 with respect to the direction in which the air flows. Therefore, no condensed water flows along the harness 40, is sprinkled in the duct 14, and is discharged into the passenger's compartment.

Since the temperature sensor 26 is inserted into the fin 24 on the upstream side of the evaporator 18 with respect to the direction in which the air flows, the temperature sensor 26 will not be detached from the evaporator 18 under forces of the air delivered by the blower 16 along the passage 12 in the direction indicated by the arrow X. The temperature sensor 26 is thus firmly held on the evaporator 18.

Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims. 

1. A vehicle air-conditioning system comprising: a duct for discharging regulated air into a passenger's compartment of a vehicle; a heat exchanger disposed in said duct for allowing heat exchange between air flowing through the duct and a temperature-regulating medium flowing through said heat exchanger; and a temperature sensor for measuring the temperature of said heat exchanger, said temperature sensor being disposed upstream of said heat exchanger with respect to a direction in which the air flows through said duct.
 2. A vehicle air-conditioning system according to claim 1, wherein said temperature sensor includes at least a portion inserted in said heat exchanger on an upstream side thereof with respect to the direction in which the air flows through said duct.
 3. A vehicle air-conditioning system according to claim 1, wherein said temperature sensor is held by a holder, said holder including a tapered inserter which includes at least a portion inserted in said heat exchanger.
 4. A vehicle air-conditioning system according to claim 3, wherein said holder is made of resin, said tapered inserter being integrally formed with said holder of resin.
 5. A vehicle air-conditioning system according to claim 2, wherein said temperature sensor is held by a holder, said holder including a tapered inserter which includes at least a portion inserted in said heat exchanger.
 6. A vehicle air-conditioning system according to claim 5, wherein said holder is made of resin, said tapered inserter being integrally formed with said holder of resin.
 7. A vehicle air-conditioning system according to claim 1, wherein said heat exchanger comprises a cooling heat exchanger, said vehicle air-conditioning system further comprising: a heating heat exchanger for allowing heat exchange between air flowing through said duct and a heating medium flowing through said heating heat exchanger, said heating heat exchanger being disposed downstream of said cooling heat exchanger with respect to the direction in which the air flows through said duct; and an air-mixing mechanism for adjusting the ratio between the flow rate of air passing through said heating heat exchanger and the flow rate of air bypassing said heating heat exchanger, said air-mixing mechanism being disposed downstream of said cooling heat exchanger with respect to the direction in which the air flows through said duct and being disposed closely to said cooling heat exchanger. 